Moisture meter?

depends on how deeply you put into the pot. the first use, wait until you would normall using finger test.. what is the measurement on the device? That's a good point to use as a trigger. The loss of weight from the pot after an irrigation = drinking, mostl. So, that too is a great way to figure out a good moisture level as measured by your device. Depending on how deeply you put it, you'll get different readings even thought it's a good time to re-irrigate. Be consistent about it and you can skip this step in future. might want to do this procedure at least 1 time with any differently sized pot or anytime you change ingredients of your substrate, just to be safe. find your reference in hindsight using your normal methods. you can systematically adjust from that point if you want to try a faster or slower irrigation trigger.